Wind power is considered one of the cleanest, most environmentally friendly energy sources presently available, and wind turbines have gained increased attention in this regard. A modern wind turbine typically includes a tower, generator, gearbox, nacelle, and one or more rotor blades. The rotor blades capture kinetic energy of wind using known airfoil principles. The rotor blades transmit the kinetic energy in the form of rotational energy so as to turn a shaft coupling the rotor blades to a gearbox, or if a gearbox is not used, directly to the generator. The generator then converts the mechanical energy to electrical energy that may be deployed to a utility grid.
Rotor blades in general are increasing in size, in order to become capable of capturing increased kinetic energy. However, the shape of a typical wind turbine rotor blade results in a relatively large aerodynamic separation region, due to the contour of the rotor blade. Specifically, the contour of the inner portion of the rotor blade adjacent to and including the cylindrical root causes such separation. In some cases, this inner portion may include 30%, 40% or more of the rotor blade. The separation region causes relatively significant energy losses by creating drag. Further, these losses are amplified as rotor blade sizes are increased.
Add-on extensions or other structures have been suggested for improving the aerodynamic profile of the inner portion of the rotor blade. Reference is made, for example, to U.S. Pat. No. 7,837,442. An issue, however, exists in effectively utilizing these structures at the cylindrical root configuration, which is necessary for facilitating connection of the blade to the rotor hub. Tapering of the extension structures in the direction of the blade root, or terminating the extensions spaced from the blade root, results in decreased aerodynamic performance.
Thus, an improved assembly that more effectively utilizes the benefits of a root-end leading or trailing edge extension would be desired.